A cobpobation



March 10, 1931. p F. s. DENISON 7,9

CIRCUIT IIAKER AND BREAKER Original Filed Jun'e 2'7, 1925 2 Sheets-Sheet1 INV ENTOR FREDERICK $.DENI5ON ATTOHNCYS 1 provements in the methods ofand apparatus lama-arc! is. mnirson,

' name, To umxmorirsnoxnwm-L This invention relates'to new and usefulimfor controlling combustion mechanism and more particularly rel zitesto such mechanisms havin avfuel feeding apparatuswhich is elect'rical ycontrolled. It 15 common especially in theart ofoil-burners' to emgloytheme-- statically controlled burners w ich control not only effects thestarting and stoppingbof the burner operation and fuel. feeding alsoignition therefor. It is highly a vantageous to employ a safety meanswhich will automatically s'to failure of combustion of the fed' fuelwhet er such failure of combustion occurs initially or intermediately.during the fuel feeding. In this novel invention, a safety m'eans isprovided which is automatically operable upon starting of the fuelfeeding to sto the same after apredetermined interval. is novel processand apparatus also includes the use of the combustion of the fuel as acontrol medium to render the safety means inoperative before completion.of its stopping unction and, further, this control medium may also beused to stop operation ofan ignition means. a

Further, this processprovides the controlling of an electricallyoperated fuel feeding apparatus which consists in closing a circuit tothe fuel feeding meansto operate the same, providing an igriition'meansfor the'fed fuel. causing the safety means upon closure of the circuitto start functioning automatically to stop thefuel feeding afteraredetermined interval, using the heat of com ustion of the function,and

while said circuit fuel as a'control medium to-render the safety meansinoperative before completion of its using the failure of combustionisclosed as a control medium to permit said safety means to function tostop the fuel feeding after a predetermined interval. v i

The object therefore of this invention is to provide a method of, andapparatus for, controlling combustion mechanisms.

Other objects of the invention will more fully appear from'the followingdescription and the accompanying drawings and will be pointed out intheannexed claims.

october 15, 1mm resume; antista c-z; reissue fledl'anuary l, 1931.Serial no. -ao;e,7a1.;

the fuel feeding u on- 1 adapted to render inoperative the. safety ormamas, mum nssmioiiiinjr ass-err:

uncommon comment, or or-DELAWARE- 3mm aathe? 'drewiigs structum ig d- 0carryout theaunas,

' objects of the invention, but it is' to be under stoodthat-theinvention' isn t'cOnfined exact features shoyvn as variouschanges ma be made-within theyscope of the claims which "'1" follow. 1'f 1 Inthe drawings: Figure 1. is a view in sideielevation-gof athermostatic member mounted sdfthat its thermostatic element isresponsive to theheat of combustion, the mountingbeing shown" insection;.

Figure 2 is a cross-sectional viewon the line 2-2 of Figure 1;: ma

ilar

Figure 3 is a ofFigure1;fy

Figu're4 view o'n the linea I is a view of the disc and inovable partsin the intermediate positionsffassumed when the. two 'of the contactsaredisenga'ged andtwoarestillenga I Figure 5 is a view similar to theforegoing but showing all contacts disengaged ".a'nd' Figure 6 is awiring diagram of the apparatus embodying the invention. I l Thisnovelprocess and apparatus maybe lexplained and illustrated in conjunctionwith the relay control mechanism forming the subject-matter of the priorpending application of the inventor hereof Serial Number 7 22,588, filedJune 26,1924. Such mechanism; its 1f struction and operation willbefirst described and then the automatic cut- 'ut or safety switch andthereafter the device which is switch when the device is'aflected by theheat of combustion.

The fuel feeding. device may include an electric motor 7 which isadapted .to operate a blower to jet the fuel, su as oil, to the burner;head, or to operate a centrifugal burner head with or without anoilpump. parts are old and well-knowh in this art and need not befurther illustrated or described. The motor 7 may receive electricalenergy from the power lines 8 and 9 through a motor switch which isautomatically controlled,- as, for example, by a thermostat in the roomor other lace to be heated. In t e form here disclosed the thermostatcom rises a submntiall ring-like bar 11 411511188 securely attached tereto a relativelystifi metallic member such as-the blade 12 formed of abar of suitable metal which is an electric conductor. As the mechanismis preferably mounted in an upright position, the blade 12 de nds fromthe thermobar 11. This ring-1' e bar is mounted, as is usual ininsulated relation.

Two terminals are an ported adjacent the bar 11 and are here in icatedas terminally pointed contacts 13 and 14. The contact 13 is electricallyconnected to the wire 15 and the contact 14 is so connected to thewire16. The starting circuit is closed across the contacts 13-14 and, inthe form shown, the circuit-closing means consists of a pair of membersadapted to be successively engaged with their respective contacts. erelatively stiff blade 12 is carried by the thermo-bar 11 and is adaptedto en the contact 13 in order to form an electric'a connectiontherewith. A second blade 17 is also carried by the thermo-bar 11bymeans of its welding to the blade 12. The blades 12 and 17 are soarranged that they terminally diverge and each bears a contact tip 18.The contact tip of the flexible blade 17 is adapted to engage the end ofthe lower contact 14. This flexible blade 17 is also provided with anaperture 19 so that the other contact 13 may freely be ends of thebacking plate, the flexible passed therethrough,-the resultant air gapproviding suflicient ,insulation between the con tact 13 and theflexible blade 17 This flexible blade is also desirably provided with areinforcing orbacking plate 21. The ligpgl a e 17 and the relativelystifl' blade 12 are welded together to present a substantially unitarystructure in electrical connection at that end, The plate 21 and blade12 are both of relatively stifl' metal and are disposed interminallydiverging relation, the flexible blade being interposed so that itsflexibility permits movement of its major portion between the backingplate and blade 12. It may also be noted that the backing plate isprovided with an aperture similar to the blade 17 for the same purpose.In addition to the thermostatic circuit wires 15 and 16, which arerespectively connected to the contacts 13 and 14, a supplemental wire 22is electrically connected to the thermo-bar '11, and hence to theblades'12 and 17. I

The switch forming the subject-matter of the previously cited pendingapplication may next be described in conjunction with its connections.The switch is referably borne by a panel usually mounted in a verticalposition. An electromagnetic'coil 23 is mounted thereon to attract,'when energized,

an armature 24 having a weighted portion 25 and mounted upon a pivot pin26. This armature lever has an arin 27 projecting beyond the pin 26 toengage and normally uphold a counterweight 28 connected to the 28normall tends to retain each tip 31 in I contact wit the respectiveterminal contacts 35 of the lead wires 32 and 33, the opening movementbeing limited "by the adjustable screw 36. Upon closure of these switcharms 29, electrical energy passes from the line'8 to the lead wire 33 tocontact 354.0 switch arm contact 31, throu h' the switch arm to post 34and, by wire 35 tothe device, to be energized such as the burner motor7, and thence'returns by wire 38 to the other 34, other switch arm 29,contacts 31-35,

32 to the other power line 9.

Thus, the counterweight 28 constantly exerts a vitational force tendingto hold the switcfirms 29 in closed "tion. But, the armature weight '25which exerts a great er force overcomes'the force of the counter weight28 and normall holds the switcharmsin open osition. fiowever, uponenergization of t e electroma et 23, the force of the weight 25 isremove and the counterweight. may close the switch-arms where theyremain until the el'ectromagnet is'deenergized whereby the weight 25 mayindirectly open the switch-arms. v

Theenergization and de-energization of the electromagnet is eifected bymeans of the thermostatic mechanism above mentioned. The two switch-arms29 are conventionally represented as tied together by the bar 39 becausethey function as a unit in pivotal movements upon their posts 34. Theelectromagnet 23 is in series with the wire 41 which is terminallyconnected to the secondary side of atransformer 42 which has its primaryconstantly energized by its shunt circuits 43-44 from the lines 32-33.The wire 16 leads from the other endbf the secondary of 7 thistransformer to the thermostat control.

' In the wiring diagram, the'parts are represented in the positionsoccupied when the blower-motor 7 is shut ofi and the thermostat, usuallypositioned in the room or lace .to be heated, is warm enough-to hol theblades from circuit-closi the lower contact 14. In-such position, the

upper contact 13 is freely passed through the alined apertures in theplate 21 and blade 17 and is out ofelectrical connection therewith whilethe other blade 12 is spaced from its contact 13. The electromagnetcircuit thus conductor elements 101, 99, 97,

' bar 11.

bar causes engagement of the stiff blade 12 with its contact 13. Thebacking plate maintains its spaced relation from the blade 12 .while theblade 17 flexibly remains in contact with its contact 14. Thus thecontacts are successively made and the. electromagnet circuit is closedacross the contact screws so that (if both contacts of the combustionthermostat are closed due to the cold condition of said thermostat) theelectromagnet is energized, its armature weight 25 is raised whichpermits the weight 28 to drop and thus to move the switch armsintoposition closing the main line circuit to the motor. This circuit isas follows: one side of the secondary of transformer 42, 16, post 103,post 98, 16, 14, 17, 12, 1s, 15, 69, '54, 64, 74, 71, 41, 34, 41, 23, 41to opposite side of the secondary of the transformer. One of the switcharms 29 carries a short arm which is electrically connected to the wire41 leading from the electromagnet to the contact 13 through thecombustion-affected thermo-switch as will be later described. However,this arm 45 is adapted, when the switch-arms are closed, to effectelectrical engagement with the relatively fixed contact 46 which is connected by-the wire 22 to the room thermo- Thus, when the switch-arms aremoved to circuit-closing position, the army 45 by contact at 46 shuntsthe portion of the wire 41 connecting the post 34 and its normalcircuit-continuation via the wire 15 to the post 13 of the roomthermostat. This condition obtains so long as the electromagnet 23remains energized and any accidental break in the current from the powerline will deenergize the electromagnet and cause the motor circuit to beopened by force of gravity acting through the weight 25 which is heavierthan the counterweight 28 and is therefore able to open the switch-arms29 against the pull of the counter-weight 28.

However, disregarding such abnormal or accidental condition, themotor-switch-arms may be caused to be opened by movement of thethermo-bar 11 when it becomes heated and successively moves the blades12 and 17 from their contacts. The circuit is not interrupted until thethermo-bar has moved a predetermined distance from the contacts. Such alag in the breaking is provided by the use of the relatively stiff andflexible contact blades and the supplemental connection for thethermo-bar and blades. Thus, as the heating thermo-bar moves from thecontacts, the stiff blade 12 is first disengaged from its post 13 and insuch position, the contact 13 and its connections via wire 15 and wiresupplementary switch arm 45 are de-energized but, the circuit from theelectromagnet is maintained across the arm 45, fixed contact 46 and wire22 to the thermobar 11 and flexible blade 17, contact 14, wire 16,transformer 42,. and wire 41 to theelectromagnet 23. or power lines arethus maintained closed and supply electrical energy to the motor 7 Whenthe thermo-bar has continued its opening movement for the predetermineddistance or lag, the flexible blade 17 is moved contact 14 and thecircuit is opened. The relatively stifi metallic backing plate 21 befromits The leads from the supply ing movable with the-blade 12 assures the,

op'eningtravehof the flexible blade 17 in timed relation to that of thestiff blade 12. When the electromagnet circuit 'is thus opened, thearmature weight 25 drops and, through the lever 27, rocks the'lightercounterweight 28 of theswitch-arms, moving the latter as well as theshort arm 45 to open positions for a subsequent cycleof operations.

This-novel process and apparatus forming the subject-matter'of thisapplication may be employed in conjunction with the above thermo-staticcontrol mechanism, which is in present use, as well as with other typesbut, as before stated, for purposes-of explanation, it will be describedand its operation pointed out in connection therewith. I

The novel safety means featured in this invention and hereinbeforementioned con- -S1StS0f an automatically operable circuitbreakerinterposed in the relay circuit and also a thermostatically controlleddevice adapted to be'mounted so as to be responsive to conditions ofcombustion automatically to' affect the operation of the circuit-breakerto interrupt the fuel feeding means or burner motor in case of ignitionfailure upon initial starting of the fuel feeding means.

The thermostatically controlled device will next be described and, asshown in Figures 1, 2 and 3, comprises the casing 45 which preferably isopen on one side as shown in Figures 2 and 3. A closure 46 is providedto close the open side of the casing asshown to prevent dust and foreignmaterial from getting thereinto and affecting the operating mechanismmounted therein. A flanged bracket 47 is secured to the casing 45*, toprovide a means for securing it to a supporting means such, for example,as the stack 48 of the furnace or heating plant. A thermo-element 49 hasone end secured to the bracket 47 and inwardly projects into the stackaffected by the products of combustion when ignition takes place. A cap51 is secured to 48 so as to be directly the end' of the thermo-element49 and has a stem 52 secured thereto which extends through'thethermo-element and into the casing 45, as particularly shown inFigure 1. The coefficient of expansion in the thermoelement, 49 isobviously considerably greater than that of the stem 52 so that whenignition takes place and the element becomes heated it will relativelyelongate sufiicie'ntly to l in Figure 2- The switch arm 53 has an arm57, rovidedthereon which is connected to the inner end of the stem 52 bymeans of a pin 58 as shown. The aperture 59 in the stem 52, throughwhich the pin 58 passes, is preferably,

elongated so as to permit the stem to relative ly move with reference tothe arm 57 when the contacts of the device are in circuit closingposition as shown in Figure-1. A tension spring 61 has one endterminally secured to the arm 57 and its other end to the casing wall,

thereby constantly exerting a pull on the arm which tends to move theswitch arm 53, and therefore the contact 54, into circuit closingposition. i

A disc 62 is also mounted upon the stud and is frictionally preventedfrom relative Y rotation thereon by means of a. tension member 63interposed between the lower face of the hub of the switch arm 53 andthe upper face of the disk 62 which rests on hub 56. (See Figure 2.).A-flexible contact member 64. having a contact tip 65 on each sidethereof, is mounted in a stud 66 secured to the disc 62 as shown inFigure l. A wire 67 electri-' cally connects the stud '66 and thereforethe contact member 64 with a terminal post 68 mounted in the wall of thecasing in insulated relation thereto. When the thermo-element 49 iscold, as when before combustion takes place, the contact screw 54 willbe moved into contact with one of the contact tips 65 of the member 64,thereby electrically connecting the terminal post 68 with a similarterminal post 69. mounted in the wall of the casing and not insulatedthereform so that current may pass from the post 68 through the wire 67,flexible member 64, contact tip 65, screw 54, switch arm 53, stud 55 andthrough the casing wall to the post 69. A third terminal post 71 is alsomounted in the casing wall in insulated relation thereto and iselectrically connected I to a post 72, mounted upon the disc 62, by

means of a flexible connection 73. A contact screw 74 is adj ustablymounted on the post 72 and is adapted to be engaged by the flexiblecontact member 64 to'close acircuit between the terminal posts 68 and71.

An important feature of this invention resides in the construction ofthe novel switch mechanism above described, and in the order in whichthe switch contacts 54,65, 74 are moved into and out of circuit-closingand circuit-opening positions by the action of the thermo-element 49which, as before stated, is directly responsive to conditions ofcombustion in the burner. These switch. contacts are so arranged thatthe time interval required to move them into circuit-opening and desiredde Imps successively open and close during each cycle of o' eration.

T e means rovided' for controllin the timed relation etween the openingan closcircuit-closing positions may be varied to any v They are alsoarranged to.

ing' of the contacts preferably consists in 'mounting upon the disc 62 apair of posts 70 and 75 having stop screws 76 and 77, res ctively, adjustably mounted therein.

stop screw 76 is adapted to be terminally enby the switch arm53-whenmoved into the position shown in Fi re 5. The

stop screw 77 hasa headed pm 78 secured thereto which extends through anaperture 7 in the. flexible member 64 so that when the contact screw 54is moved out of contact with the tip 65 of the member 64, asparticularly shown in Figure 5, the member 64 will engage the head ofthe pin 78 which will thereby prevent its further movement, therebyallowing the contact screw 54') be moved vout of electrical contact withits complemen tary tip 65 of the member 64 as shown. Ob-

viously the post 75 is insulated from the disc 62 in order to preventthecurrent from short circuiting between the posts 75 and 72. By adjustingthe stop screws 76 and 77 the air gap between the contact screw 54, andits complementary contact tip 6.5 and also be-. tween the contact screw74 and the'other tip I 65 onthe op osite side of the flexible member 64,may he increased or decreased to obtain the desired time interval in theopening and closing of the contacts.

.In the operation of the above switch mechanism, it will be noted thatwhen the ofi-set arm 57 ofthe switch arm 53 is. moved by the action ofthe thermo-element 49 the disc 62 will also tend to rotate upon the stud55 as a result of the tension member 63 frictionally connecting it withthe hub of the switch arm 53. Such rotation of the disc 62 with the arm53 will cause the contactsto remain in closed position as a result ofthe flexible member 64 and the post 72 being carried by the disc.- Meansare therefore provided for interrupting the rotation of the disc at apredetermined periodso that continued rotation of the switch arm uponthe stud 55 ,Will cause the switch contacts. 54, 65, and 74 to besuccessively nio'ved out of contact with one another as shown in Figure5. .Themeans providedjforthus interrupting the rotation of the disc-62preferably consists of securing a pin -79-to the disc so that it de endstherefrom into the path of-a small 0 -set lever 81 which has one endpivotally connected to the casing wall by means of a pin 82. Theconnection between the lever 81 and the. casing wall is such that itwill be trictionally held in its adjusted itions. f I

Referring to -i' ure 1, it will be noted that the pin 79 is"o ut 0%contact with the lever 81, thereby allowing the disc 62 to rotate withraces the switch arm 53 until the -pin engages the lever 81 as shown inFigures 4 and 5. After the pin thus engages the lever 81- rotation ofthe disc will be interrupted and the switch arm 53 will continue to movefollowed by the flexible member 64, the tension of which tends to keepit in electrical contact with the contact screw 54. When the switch arm53 reaches the pgsition shown in Figure 4, the flexible mem r will engthe head of the pin 78 and its movement Wlll thereafter cease, therebyallowing. the contact screws 54 to be moved out of electrical contactwith its complementary tip 65 of the member 64 as shown in Figure 5.Upon the return movement of the switch contacts, or when they are movedinto circuit-closing position b the cooling stop pin 7 9 engages a stoplulg ways so.

of the thermo-element 49,'the isc 62 will be rotatedsimultaneousl withthe switch arm 53 by the action of e spring 61 until the 83 mounted inthe casing wa as shown in igures 1 and 3. As soon as the pin 79 thusengages the stop lug 83, the switc contacts will be successively m vedinto electrical connection with one another as previously described. Bymounting the disc and switch contacts, as above described, apredetermined clearance will albe maintained between the contacts whenin open position, thereby always causing the ignitionicircuit to bepresented a redetermined time after the burner has n interrupted andalso before the circuit breaker circuit is prevented.

Although it has been shown that the disc 62 moves when the arm 57 ismoved by the thermostat,- and also that stops 81-83 limit disc motionwhen engaged by pin 79, yet it is obvious'that this need not necessarilybe so, and that these stops and pin may be dispensed with, if thecontact surfaces between the elements 56-62 and lower surface of the hubfor example.

. wise direction without moving the of arm 57 and upper surface oftension element 63' are related in a certain manner. For example, if thecontacting surfaces of disc 62 and post 56 are rough-machined and if,they aremade of brass, and if the lower surface of the hub of arm 57 andthe upper surface of the spring 63 are well polished, the disc-62 willnot be driven frictionally by the arm 57, but is frictionally preventedfrom moving, by tension member 63,

until arm 53 engages stop or contact 76, or

stop or contact 74, after which the disc will be moved ifinotion of arm53 continues to move in the same direction.' In such .acase, then let itbe assumed that the element 49 is heating. The elements 53 will thenmove in clockdisc 62, the contacts 65, 74 will first be broken, and thenthe contacts 54 and 65, then the arm 53 will come in contact with thescrew 76 and on continued motion in the same direction will entrain ormove the disc. On cooling motion of the element 49 the arm 53 will movein 'rotatably mounted support 62,

counterclockwise direction and the contacts 54-65 and -7 4 will besuccessively made.

After these contacts are made, and on continued motion of the element 49in the same direction as it cools, the 'disc 62 will move incounter-clockwise direction. Itis thus seenthat the element 53 operatesbetween two sto s or contacts 74, both fixed to the disc, an element 53alternately acts through these sto s or contacts to move the discalternatively m opposite directions, Thus, a pair of elements theequivalent of 53 and 62 are mounted to move independently of oneanother, one of these elements has a pair of contacts, or stops, 74-76,against which, or through which, element 53 operates, so that oneelement can alternately move the other in opposite directions. It isalso seen that a tarded against rotation is rovi this support has a air0 contacts and that there is an arm in ependently mounted and swingableagainst the contacts, or posts, or

Stags. J

eferring to Figure 6, it will be noted that the wire 15 leading from thecontact 13 of the room thermostat is connected to the terminal post 69of the above described switch mechanism which will hereinafter bereferred to as the combustion thermostat. A wire 84 also leads from theterminal 69 to one side of an ignition circuit and 86, the latter beiconnected by a wire 87 to the secondary o a transformer 88 as shown. Theother side of the transformer secondary is connected to the terminal 68'by means 0 a wire 89. The form of i means shown in Figure 6 referablycomprises a gas valve 91' which is automatically operable by means of arelay coil 92 connected in series with the wires 85 and 86 and'thereforethe secondary side of the transformer 88. A spark coil 93, of ordinaryconstruction, also has one of its windings connected in series with thetransformer 88 through the combustion thermostat while the high tensionwinding thereof is connected in series with a spark plug 94 as shown.The above .described method of ignition is commonly known as acombination gas and spark and is well known in the art. The wire 41leading from the post 34 of the motor switch is gnition 'eldably reed,and that comprising the wires connected to the third terminal post 71 ofthe ;of the safet' means will be described in con-" nection wit thethermostatically controlled burner motor and therefore e fuel feedingmeans. The circuit-breaker shown diagrammatically in Figure fi,comprises a conductor 1 strip-97 secured to a terminal post 98 to whichis connected one end of the portion of the wire 16 leading from thecontact 14 of the i room thermostat. A movable switch arm 99 is securedto a resilient member '101mounted upon a supportingstrip 102 by means ofa terminal post 103. The terminal posts 98 and, 103 obviously areinsulated from the supporting stri 102. [One end of the portion of thewire 16 eading from the transformer 42 is connected to the terminal post103. These two posts 98 and 103 are therefore electricall connected inseries with the wire 16 whic leads from the post 14 of the roomthermostat to the transformer 42'so that the normal engagement oftheswitch arm 99 with the conductor strip 97 of the circuit breaker doesnotinterrupt the thermostatically controlled circuit at the wire 16.

The means provided for automatically moving the switch arm 99 out ofcontact with the conductor stri 97 to break the circuit, in case ofignition ailure, preferably-consists of athermo-bar 104 havin one endsecured to a sup ort 105 secured to the supportingstrip 102. he outer orfree end of the thermo-bar has a reduced portion forming a tab 106 whichis adapted normally to be received within an angular recess provided inthe depending off-set end 107 of the movable-switch arm 99 of thecircuit breaker. A heating coil 108 is coiled about the thermo-bar andhas one end connected by a wire 109 to the wire 87 leading, to onesideof the secondary of the transformer 88. The'other end of the heatingcoil is similarly connected by a wire 111 to the wire 41 leading fromthe intermediate contact post 71 of the combustion thermostat to thepost 34 of the motor switch. The circuitbreaker is so constructed andarranged that, upon the passage of current through the heating coil 108for a predetermined interval, the thermo-ba-r 104 will be warped out ofengagement with the ofi-set end 107 of the movable 'switch'arm 99, whichis mounted so that its tioned for normal operation by the manualre-setting of the circuit-breaker switch arm 99, such, for example, asby a push button 112, preferably mounted in the supporting strip 102 ofthe circuit-breaker.

In the operation of this novel safety means iii-connection with thethermostatically con- '46 and the blade 45. vFurther coolin trolledrelay circuit of the burner motor and fuel feedingmeans, the apparatus,after a predetermined room temperature is reached, will .be in theposition showninvFigure 6, wherein it will be noted that the contactblades 12 and. 17 of the room thermostat are out of electrical contactwith the 13 and v 14. When thus positioned the circuit through wire 16of the relay will be broken atth'e room thermostat thereby causin theelectromagnet 23 to become de-energized, which will cause the motorswitch to be automatically opened by the gravitational drop of theweighted portion 25 of the armature 24. Such o of the motor switch willalso cause the switch arm to be moved out of electrical contact with thecontact 46, whereby the holding circuit for relay 23 is broken. When theroom thermostat and mbtor'switcharein inopera-v. 171V!) positions, asabove described, the entire burner aplparatus will be interrupted,thereby causing t e thermo-element of the thermostat to cool with theresult that the contacts 54, and 74 will be moved into electricalconnectiim with one another, as shown in Figures 1 an 6.

When the contacts of the combustion there niostat are thus closed, thewire 41 of the relay circuit will be electrically connected to the wire15 leading to the room thermostat so that current may flow from theelectro-m'ag-' net 23 through the wire 41, combustion ther-v mostat,wire 15 to the post 13 of the room the tip 18 of the ,blade 12 is movedinto con-' tact with the contact screw 13. .Itwill be noted that whenthe contacts of the combustion thermostat are in closed position, thatthe heating coil '108 and also the tion means will be connected inseries with e secondary of the transformer 88 so that when the burnermotor resumes operation by the automatic closing of the motor switch bythe action of the room thermostat that ignition will also besimuletaneously resumed.

As soon as the room temperature to lower the contacts 18 of the blades12and17 of the room thermostat will 'move towards thermostat where it willbe interrupted until i the contact, screws 13 and 14 until the tip18 eof the blade 17 is moved into electrical connection with the contact 14.Such connection, however, will have no effect on the apparatus as aresult of the blade 12 being out of contact with the contact 13, andalso as a result of the separated relations of contact of the room willcause the tip 18 of the b 7 e12 to be moved into electrical connectionwith the contact screw 13 thereby completing or closing the relaycircuit which will be as fol lows :-'From the secondary of thetransformer 42 through the wire 16 and circuit breaker inter osedth'erein, contact screw 14, blades 17 an 12,,contact screw 13, wire 15,to the terminal post 69" of the combustion member 64, post 72,connection 73 to the intermediate terminal post 71 thence through thewire 41-to' the electromagnet 23 and back to the other side of thetransformer secondary. Closing of the above circuit will cause theelectromagnet 23 to become energized resulting in the armature 24 beingupwardly drawn therebg resulting in the weight28 drop ing anautomatically closing the switc arms 29. Such closing of the motorswitch will cause the motor 7 and the igni tion means to resumeoperation with the resultant operation of burner under normalconditions. Referring to Figure 6, on ener gization of the transformer88 dueto .closure of the motor switch 29, the ignition, and coil 108 ofthe circuit breaker, are energized (both contacts of the combustionthermostat being now closed). The circuit for the ignition is asfollows: one side of the secondary of the transformer 88, wire 89, post68, wire 67, post 66, blade 64, contact 54, arm 53, stud 55, casing 45,post 69, wirev 84, 92, 86, 87, to the opposite side of the secondary ofthe transformer 88. The circuit for the coil 108 is as' follows: oneside of the secondary of the transformer 88, 89, 68,67, 66, 64, 72, 71,41, 111, 108, 109, 87 to o posite side of the secondary of the transormer 88. As soonas combustion has thus been started, the heat ofcombustion will affect the th'ermo-element 49 causing it to elongate andthereby actuating the switch'mechanism mounted in the combustionthermostat.

The first movement of the thermo-element 49 upon combustion resumption,causes one of the tips of the blade 64 to be moved out of electricalcontact with the contact screw 74, see Figure 4, thereby breaking thestarting circuit to main switch operating device 23. After breaking ofthe circuit mentioned, the current to the heating coil 108 is stillmaintained through the following circuit: from the lower side of thetransformer secondary 88, 109, 108,111, 41, 45, 46, 22, 11, 12, 13, 15,69, 53, 54, 64, 66, 67, 68, 89, to the 0pposite side of transformer 88.The electromagnet 23, however, will remain energized to attract thearmature 24 as a result of the switch arm 45 being in engagement withthe contact 46 and the blades 12 and 17 still being in contact with thescrews 13 and 14. When the above condition exists the electromagnetcircuit will be as follows From one side of the'secondary of thetransformer 42 through the wire 16 and circuit-. breaker to the contactscrew 14 of the room' thermostat; thence through the blade 17, coiledthermo-bar 11, wire 22, contact 46, switch arm 45, wire 41 to theelectromagnet 23 and thence back to the other side of the transformer42. i

If the element 49 continues to expand by flexible switch member 64 has eapplication of heat, the contacts 65-54 are broken as shown in Fi re 5,because of the continued motion of t e arm 53 after ,the I aged its stop78 as shown. The breaking 0 contacts 54-65 breaks the ignition circuitand the circuit to the heating element .108, and this inactive conditionof 92 and 108 obtains until the room temperature rises sufiiciently tocause contacts 12 and 18 to leave sts 13 and 14, at which time thecircuit to t e magnetic device 23 is broken and the entire ap aratusrendered, inoperative so that com ustion ceases. Upon such interruptionof combustion the thermo-element 49 of the combustion thermostat willbegin to cool, and first resent or close the ignition circuit afterwhich the circuit-breaker circuit will be closed and the safety meanspositioned for the next cycle of operation.

It will be noted that sufficient electrical energy for closing relay 23,and raising armature 24 (closing motor switch 29) cannot be had, unlessboth contacts of the combustion thermostat are closed (due to theabsence of of temporary power failure and immediate resumption thereofwhen the burner is normally running and the room thermostat is inelectrical contact with the contact screws 13 and 14, it will beimpossible for the burner to resume operation until after thethermoelement 49 of the combustion thermostat has cooled sufficiently topresent or close the ignition circuit .before the electromagnet becomesenergized to close the motor switch. This is accomplished-by the timedrelation of the opening and closing of the switch contacts in the stackthermostat which are so arranged that the ignition circuit is alwaysclosed beforethe motor or power feeding means is started after havingbeen accidental- 1y interrupted.

.Inthe event of ignition failure when the fuel feeding means is startedby the closing of the main motor switch by the indirect action of theelectromagnet 23 and the roomv thermostat, the thermo-element of thecombusthe circuit-breaker circuit'to render it inoperative, sothat uponnormal operation of the burner the circuit-breaker will always remain inclosed position; The initial starting operation of the burner ignitionunder normal' conditions will be started simultaneously with thestarting of the motor or fuel-feeding means, and at the same timecurrent will be caused to flow through the heating coil 108 of thecircuit breaker which circuit, however, will soon thereafter be openedthrough the combustion thermostat after combustion is started,'afterwhich ignition will subsequently be interrupted and the burner willcontinue to function until interrupted by the action-of the roomthermostat.

Having thus described my invention what I claim as-new and desire tosecure by Letters- Patent is:

.1. A thermostatically operable device for opening and closing electriccircuits, comprising in. combination a thermo-element and a supportingmeans therefor, a contact movablv mounted'upon said supporting means andhaving a connection with said thermoelement, a rotatable disk, aflexible contact f member mounted upon'said disk and adapted to beengaged by said movable contact, a complementary contact also mounted uon the disk adapted to be engaged, by said exible contact member wherebyupon actuation of said movable contact by the thermoele-- ment, all ofsaid contacts will be successively -moved into and out of electricalcontact wit one another. V

2. A pair of elements mounted to move independently one having a pair ofcontacts against which the other element operates so that one elementcan alternately move the other in opposite directions, a thermaldevioeconnected to move one of the elements. a

3. A pair of elements mounted to move independently one having a pair ofcontacts, against which the other element operates so that one elementcan alternately move the other in opposite directions, and a thermaldevice connected to move one of the elements, and means for yieldablyretarding the motion of that element which is not connected with saidthermal device.

4. -A' pair of elements mounted tomove independently one having a pairof contacts against which the other element operates so 'that oneelement can alternately move the other in opposite directions, a thermaldevice connected to move one of the elements, means push button 112 toreset for yieldably retarding the motion of element whlch l is notconnected with said thermal device along with additional means forlimiting its movements in opposite direcgageable with said arm to limitits movement 7 toward the element when said element re cedes therefromtoward the opposite contact of the pair, the arrangement being such thatwhen the element is engaging that opposite contact, the switch arm is incircuit making condition only with the third contact.

6. A pair of elements mounted to move independently one having a pair ofcontacts against which the other element operates so that one elementcan alternately move the other in opposite directions, a thermal deviceconnected to move one of the elements, means for limiting movementsalternatel I in opposite directions of that element which is notconnected with said thermal device, a switch arm operativevbetween oneof the pair ofcontacts and that element which operates between thecontacts, and a third contact engageable with said arm to limit itsmovement toward the element when said elemen't recedes therefrom towardthe opposite contact of the pair, the arrangement being such that whenthe element is engaging that opposite contact, the switch arm is incircuit making condition only with the third contact.

, 7. A pair of elements mounted to move independently one having a pairof contacts against which the other element operates so that one elementcan alternately move the other in opposite directions, athermal deviceconnected to move one of the elements, means for yieldably retarding themotion of that element which is not connected with said thermal device,a switch arm operative between one ofthe pair ,of contacts and that 8. Asupport rotatably mounted and yieldably retarded against rotation andhaving a pair of contacts, an arm independently mounted and swingableagainst the contacts and a thermal element arranged to swing the arm. 11

, element which operates between the contacts,

9. A sup ort rotatably mounted and yieldably retardgd against rotationand having a pair of contacts, an arm independently mounted andswingable against the contacts and a a thermal element arranged to swingthe arm, and having a lost motion connection therewith, and meansyieldably urging said arm towards one of the contacts.

10. A support rotatably mounted and m yieldably retarded againstrotation and having a pair of contacts, an arm independently mounted andswingable against the contacts and a thermal element arranged to swingthe arm and having a lost motion connection therewith, means yieldablyurgin said arm towards one of the contacts, said t ermal element movingin one direction against the action of said yieldable means to draw ittoward an opposite contact, and means to limit movement of the supportin op osite directions when said arm is correspon ingly moved by thethermostatic element and when in engagement with a contact. In witnesswehereof, I have hereunto set my hand this 10th day of J anua 1931.FREDERICK s. nn n isou.

